The long-term goal of our research program is the development of tactile aids for the deaf and deaf-blind that will enable the tactile sense to serve as a substitute for hearing. The research proposed in this application constitutes an essential component in a program directed toward an improved understanding of the capabilities and limitations of various encoding and display schemes for the tactile communication of speech. More specifically, the proposed research consists of an in-depth study of the Tadoma Method of speech communication. In this method, the "listener" receives speech information by placing his hand on the talker's face and monitoring actions associated with the speech articulation process. Although this method of tactile speech communication has been used, apparently successfully, by a number of deaf-blind individuals for many years, very little is known about it scientifically. The proposed research includes a survey of Tadoma use; an experimental study of Tadoma involving deaf-blind, highly experienced Tadoma users; and an experimental study of Tadoma involving normal-hearing, laboratory trained subjects. The study involving deaf-blind Tadoma users includes detailed tests of speech reception capabilities, measurements of speech production capabilities, and exploration of linguistic competence. We believe that this research, which will be highly systematic and analytic in style, will demonstrate that tactile communication of speech is indeed possible, increase understanding of the Tadoma Method, and provide important background knowledge for the study and evaluation of tactile speech communication systems that employ artificial devices.